Narcolepsy

Narcolepsy is a neurologic disorder that is incurable and therefore requires lifelong treatment. Excessive daytime sleepiness is the most common symptom and can be partially controlled by medications. The pathognomonic symptom of narcolepsy is cataplexy, emotionally induced muscle weakness, which can be the most disabling symptom for many patients. Also, hallucinations that typically occur at sleep onset or muscle paralysis that occurs upon awakening from sleep, called sleep paralysis, occur in many patients. Additional symptoms include fragmented nocturnal sleep and episodes of automatic behavior. Narcolepsy typically has its onset in the first 2 decades of life and may commonly be misdiagnosed. It produces reduced quality of life and, because of the sleepiness, can interfere with memory, concentration, and other cognitive abilities. The cataplexy may predispose the patient to injury because of the muscle weakness or falls. Narcolepsy with cataplexy is now known to be associated with a loss of the hypothalamic neuropeptide hypocretin. An autoimmune basis for the disorder is suspected. Effective treatment of the symptoms usually requires medications although some patients manage their symptoms behaviorally. Most patients require the use of two or more medications, one to treat the daytime sleepiness and the other to control the cataplexy. With the recent availability of sodium oxybate, some patients can control both the daytime sleepiness and cataplexy with one medication.